978 POSITION OF THE GENERA HYDROCOTYLE, ETC. 
true H. perforatum. Tt is included, by Professor Van Heurek, in his 
first fasciculus of rare and critical Belgian plants, and a large bundle 
of Belgian specimens gathered by the Professor is now before me. A 
plant grows sparingly, in the neighbourhood of Thirsk, in similar 
situations to the true H. perforatum, with conspicuous black lines in 
the furrows of the outer surface of the petals, and with some of the 
lower leaves dotted very sparingly with pellucid points, whieh I cannot 
otherwise than identify with Jineolatum. At the same time I cannot 
see that it is more than a variety or mere form of our common species. 
In a large bundle of our common H. perforatum in a fresh state, now 
before me, the length of the peduncles is very variable; in some of the 
specimens most of the flowers are sessile, or nearly so; in most of them 
the stalk of the flower, at the end of a branch, is shorter than the 
calyx ; but the peduncles of most of the lateral flowers are longer than 
the calyx; and this is also the case with the Belgian and British ex- 
amples of Zineolatum. In none of my specimens does M. Boreau's 
character of “ pedicels longer than the ealyx " hold good, without 
exception. The leaves of H, perforatum are very variable in shape. 
In the speeimens now before me the measurement of the fully-developed 
leaves of the main stem varies from three-quarters of an inch broad 
by rather more than an inch long to from three-eighths of an inch 
broad by an ineh long; and in one of my dried specimens, from 
Aysgarth Force in Wensleydale, the leaves are fully an inch long by 
only a quarter of an inch broad. The shape of the sepals also varies 
somewhat, in concomitance with the shape of the leaves. 
ON THE POSITION OF THE GENERA HYDROCOTYLE, 
OPA, COMMIA, AND BLASTUS IN THE “NATURAL 
SYSTEM. i 
By BERTHOLD SrgwaAxN, Pu.D., F.L.S. 
I. Hyprocorye, Zinn. 
The genus Hydrocotyle, though represented in Europe by two or three 
‘Species and passed through the hands of innumerable local botanists, 
has as yet not been placed in its true position in the natural system. 
Every one regards it as a member of the Natural Order Umbellifera, 
